code: def test_custom_metric_computation_regression():
      parms = {"ntrees": 3, "max_depth": 5}
      (model, f_test) = regression_model(
          H2ORandomForestEstimator, custom_mae_mm(), parms
      )
      print(model)
      assert_correct_custom_metric(
          model, f_test, "mae", "Regression on prostate"
      )
  
file_path: h2o-3/h2o-py/tests/testdir_algos/rf/pyunit_custom_metrics_pubdev_5088.py
imports: import sys
  import h2o
  from tests import pyunit_utils
  from tests.pyunit_utils import CustomMaeFunc, CustomRmseFunc, assert_correct_custom_metric, regression_model, multinomial_model, binomial_model
  from h2o.estimators.random_forest import H2ORandomForestEstimator
label_desc: Use image node_id 3 for calling a global function with example usage: test_custom_metric_computation_regression() without return types